This invention relates to a method of depyrogenating biological and pharmaceutical products.
In the development and production of biological and pharmaceutical products and particularly various proteinaceous substances used for biomedical and therapeutic purposes, the problem of contamination with pyrogens (endotoxins) is ever present.
Pyrogens are lipopolysaccharides (LPS) derived from the outer cell wall of gram-negative bacteria. They are toxic materials which are also known as "endotoxins" to distinguish them from toxic substances synthesized and excreted by the intact bacterium. Pyrogens have numerous biologic activities which include the production of fever, activation of clotting mechanisms and induction of shock. Consequently, it is essential that pyrogenic substances be removed and the causative bacteria be rendered innocous by sterilization or other such treatment of the final biological or pharmaceutical product.
Prior methods for inactivation of pyrogens comprise extensive and rigorous treatment with heat, acid or alkali, filtration of insoluble pyrogens or removal by adsorption with gels, ion-exchange resins and various other such adsorbent materials. Most of these methods are burdensome, time-consuming and costly.
Further background on the properties and effects of pyrogens can be had by reference to a paper by Elizabeth Work entitled "Production, Chemistry and Properties of Bacterial Pyrogens and Endotoxins" in "Pyrogens and Fever", Ciba Foundation Symposium, 1971, pp. 23-47, edited by Wolstenholme and Birch, published by Churchill Livingstone; and a paper by D. C. Morrison and R. J. Ulevitch entitled "The Effects of Bacterial Endotoxins on Host Mediation Systems" in Amer. J. Pathol. 93(2), 527-601 (1978).